1993 Toyota Pickup No start after 10-15 min hot soak

Engine Performance problem
1993 Toyota Pickup 4 cyl Four Wheel Drive Manual

After I run the engine until it gets to operating temp and let it sit for 10-15 minutes it will not restart. If I wait a bit longer it will start but runs quite rough. I have replaced the igniter, coil, O2 sensor, ecm thermo switch, dist cap and rotor, spark plugs, air filter, fuel filter. I have tested the fuel pressure regulator, the switch that controls the vacuum to the regulator, the pickup coil all ok. I replaced the ecm with a known good ecm. I checked the compression on all the cylinders as normal when cold and hot. The spark and timing are excellent when hot and cold. I did notice that the center two injectors aren't clicking like the outer two injectors if I can get it to start after the hot soak. But they all click the same when I start it cold. I also checked and found no vacuum leaks at any of the lines or intake manifold. There are no codes in the ecm, but can get one to set if I disconnect an emmisions component. With my scanner hooked up all readings are normal even when it is running rough with no codes. Thank you for your help.I am at the point where a half a stick of dynamite might be the solution.